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Re: deterministic naming of blank nodes

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 20 Oct 2014 17:47:15 +0200
Message-ID: <54452E83.30809@w3.org>
To: Sampo Syreeni <decoy@iki.fi>
CC: Alan Ruttenberg <alanruttenberg@gmail.com>, David Booth <david@dbooth.org>, Tim Berners-Lee <timbl@w3.org>, SW-forum Web <semantic-web@w3.org>, Pat Hayes <phayes@ihmc.us>
On 10/07/2014 10:25 PM, Sampo Syreeni wrote:
> On 2014-10-07, Sandro Hawke wrote:
>
>> That may be true, but it is hard for me to see how any benefit this 
>> could bring would outweigh the absolute pain in the ass it would be 
>> for everyone to change their RDF stacks.

It was not me who said that.   That was Alan Ruttenberg.

>
> So, why not subdivide the process? It ought to be easy and efficient 
> enough to detect a rather expansive subset of graphs which do admit 
> unique and efficient labeling. At the very least graphs which only use 
> a blank node precisely twice (to define something and to refer to it 
> once as in the bracket notation) are pretty simple, using a simple 
> hash table with counters -- that perhaps being the commonest case as 
> well.
>
> If the test succeeds, define a unique labeling based on the rest of 
> the attributes of the triple and lexical ordering; if not, ask the 
> user whether general graph isomorphism comparison is wanted, and if 
> so, do that, somehow signaling that it really went that far (perhaps 
> inband in the format of the labels? or out of band as the case may 
> be); if not, or if you can't do graph isomorphism in your code, then 
> slap on nonunique labels, again differentiating them somehow from the 
> first two cases.
>
> That is certainly not an easy or clean solution, but it doesn't break 
> the stack, and it works in most of the places where you want to do 
> fast path processing under the assumption that in fact the labels are 
> canonical, and can be relied upon to have 1-1 correpondence from 
> syntax to node.

I agree.   Does anyone have a good sampling of the LOD cloud we could 
easily use for this experiment?

      -- Sandro
Received on Monday, 20 October 2014 15:47:26 UTC

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